Print your own bones!
From dentures to jaws and hips – how British scientists can now help you to...
IT SEEMS like something from a science-fiction film. A severely injured motorcyclist has his face rebuilt using titanium plates produced by a 3D printer – a machine that creates three-dimensional, useable objects by building them from thin layers of plastic or metal.
But the treatment that put Stephen Power in the headlines last week is far from a one-off medical miracle. In fact, you may have been benefiting from this remarkable technology for years at your local dental practice.
NO MORE CHEWING RUBBER
In dentistry, 3D scanners and printers are used to produce moulds of the mouth, replacing the unpleasant experience of having to bite into gunk-like impression material.
‘For 100 years dentists relied on manual impressions, made using a mouth-shaped tray filled with a quick-setting rubber,’ says Eric Erickson, of Stratasys, the main supplier of 3D printers for dentistry.
‘This was used to make a plaster of Paris model of the patient’s teeth, and helped dental technicians hand-craft crowns or dentures.
‘Now we scan the mouth, create a computer model and send it to a 3D printer.
‘Not only is that far quicker, it means an absolutely precise representation of your mouth and teeth, and therefore better fitting crowns or braces.’
Dentists and surgeons regularly use 3D-printed surgical aids too, such as a mouth-shaped sheet with a hole for the drill to be used for implants. Mr Erickson says: ‘Before, things were done simply through knowledge and experience, but these guides use exact replicas of your mouth to show exactly where to drill, meaning fewer mistakes like hitting nerves.’
Up to ten per cent of dentists use these digital technologies.
MOTORING AHEAD
The 3D technology first emerged in the 1980s and is commonly used by Formula 1 teams. In fact, the engineering centre at Cardiff Metropolitan University, which worked with the surgeons reconstructing Stephen Power’s face, was originally focused on producing prototypes for the motor industry.
The technique works much like normal document-printing but instead of recreating a two-dimensional image from the screen, it translates a 3D virtual model on the computer into reality. Objects are formed from a series of layers or particles, rather than by chiselling a shape from a block of material – meaning excellent precision and better efficiency. In the case of Mr Power, X-ray scans of his head were used as a starting point, with new guides and plates built virtually before being printed.
STRIVING FOR ACCURACY
Last month it was revealed that orthopaedic surgeons in Newcastle had created a titanium pelvis through 3D printing. The replacement was for a patient with a rare bone cancer who had to have half his pelvis removed to stop the disease spreading.
Paul Unwin, chief technical officer at Stanmore Implants, which produced the pelvis, says: ‘In difficult cases, 3D printing can be more appropriate as it’s good for complex shapes, and we can build structures like lattice work that allows bone to grow into it. We’ve produced 11 pelvises in this way, and nine shoulder blades – these can be just 2mm thick in places.’
Maxillofacial surgeon Adrian Sugar, who carried out the operation on Mr Power at Morriston Hospital in Swansea, adds: ‘We’ve been using 3D printing for 12 years in pretty much every aspect of reconstructive surgery.
‘For planning operations we use it to produce both virtual and physical models of the skull, and the technology has made surgery easier and far more accurate. Instead of spending many hours in the operating theatre thinking, we now spend many hours before surgery thinking.
‘To some extent it’s more timeconsuming but the surgery is more accurate – we can produce a much more reliable outcome by doing things in this way.’
PRINTING SKIN . . . AND ENTIRE ORGANS
In future it is likely such techniques will be used in hospitals throughout Britain. ‘The challenge now is to make this a quicker, cheaper, more manageable process,’ says Mr Sugar.
The technology is evolving fast and has vast potential, particularly for prosthetic limbs. ‘It could reduce two weeks’ manual work to a night’s printing, and produce limbs that fit better too,’ says Ted Varley, of prosthetics firm RSL Steeper.
There is even scope for printing entire organs. A kidney, strips of liver tissue and human blood vessels have all been created using 3D printers – a process known as bioprinting that works through cartridges loaded with human cells.